Printing, and in particular direct printing, on containers is known. A polychrome print image on a container is often an essential element of the equipping of the container in much the same way that a conventional label is an essential element in labeled containers.
Electrostatic print heads, such as inkjet print heads or print heads known under the designation “Tonejet”, i.e. print heads that operate according to the inkjet printing principle or Tonejet principle and that exhibit a plurality of single nozzles disposed sequentially in at least one row on an active print head side in a print head longitudinal axis and which can be individually triggered to dispense ink, printing ink and/or coatings and protective paints, are often used in this regard.
One problem encountered in particular with a printing apparatus for the printing of containers using print heads that operate according to the inkjet printing or Tonejet principle, is that during the printing process, some of the printing ink does not land on that region of the exterior surface of the container that is to be printed upon. It is instead sprayed out into the surrounding air where it forms an aerosol consisting of finely distributed ink or printing ink droplets. These atomized ink droplets then settle undesirably on elements of the printing apparatus. This causes contamination that can only be removed with a considerable amount of cleaning.
Known printing apparatuses are further problematic in that, especially at high rates of production, the containers are moved at high conveying speeds during printing. One consequence of this is that swirling air currents introduce turbulence around the containers. This deflects the printing ink in random ways and impairs image quality.